1. Field of the Invention
Because of the wide use of drugs derived from digitalis in the treatment of the cardiac patients and its substantial side effects, it is important to monitor the level of these drugs in the bloodstream of the patient. Digitalis is a complex mixture which includes digoxin and digitoxin which are the glycosides of digoxigenin and digitoxigenin.
A satisfactory method for assay for the active components of digitalis should be sensitive to the low concentrations of the components which will be present in blood serum. In addition, the assay should be highly specific for the materials of interest, so as to accurately reflect the presence of those materials and not other materials of similar structure. That is, there should be a minimal amount of cross reactivity in order to preclude false positive results. Desirably, the assay should require only small samples, should be rapid, should require a minimum number of manual steps, and should be useable on generally available equipment. Other desiderata include ease of handling of the reagents, stability of the reagents during storage and use, freedom from interference from naturally occurring contaminants, and being reasonably safe in handling.
2. Description of the Prior Art
See the references cited in the parent application, now U.S. Pat. No. 3,817,837, which is incorporated herein by reference. See also U.S. Pat. Nos. 3,791,932, 3,839,153 and 3,850,752.